Underreamer.



W. M. KECK.

UNDERREAMER. APPLICATION FILED ocnza. 191s.

2 SHEETS-SHiiT 1.

A TTOR NE Y4 Patented May 15,

moved and replaced.

the lower end PATENT WILLIAM Id. KECK, 0F COALINGA, CAIIFORNIA.

UNDERREAll/IER.

Specification of Letters Patent Patented May 15, 11%1 *t.

Application filed October 28, 1916. Serial No. 128,243.

To all whom it m up concern:

Be it known that I, WILLIAM M. Knon, a citizen of the United States, residing at Coalinga, county of Fresno, and State of California, have invented certain new and useful Improvements in Underreamers, of which the following is a specification.

My invention relates to an underreamer, for reaming wells below the bottom of the well-casing, and more particularly to an underreamer adapted for use in combination with a drill-bit.

The object of my invention is to provide an 'underreamer of such construction that comparatively little wear can occur at any point except the cutting or reaming edge of the cutter member, which may be easily re- This is accomplished by providing large bearing surfaces or seats for said cutter, as will be hereinafter fully described with reference to the accompanying drawings, wherein- --Figure l is an elevation showing my underreamer, with a drill-bit attached thereto, within the well-casing, the well-casing being shown in section. I

Fig. 2 isa vertical. section, enlarged, of my underreamer within the well-casing, showing the cutter in retracted position.

Fig. 3 is a transverse section, enlarged, taken in the direction of the arrows on the line 3-3 of Fig. 1.

Fig. 4 is a transverse section, enlarged, taken in the direction of the arrows on the line l-l of Fig. 1.

Fig. 5 is a transverse section taken in the direction of the arrows on the line 5-5 of F ig. 2.

Fig. 6 is a transverse section talrcn in the direction of the arrows on the line 6-6 of Fig. 2.

Fig. 7 is a part-sectional elevation showing the underreamer partly withdrawn into of the well-casing, the cutter being in its e tended, or operative position.

Fig. 8 is a sde elevation of the central and lower portion of the underreamer, the cutter being viewed from its face, instead of its side, as in Fig. 7.

Fig. 9 is a transverse section taken in the direction of the arrows on the line 9-9 of Fig. 7'.

F 10 is a transverse section taken in the direction. of the arrows on the line lO-10 of Fig. 7.

Fig. 11 is a transverse section taken in the direction of the arrows on the line 11-1l of Fig. 7.

In the drawings, the reference numeral 1 designates the which is substantially cylindrical in form, and of a diameter to fit loosely within the well-casing 2. At its upper end, this body 1 is provided with suitable means, as, for example, a tapered screw-thread 3, for attachment to a cable or rod, not shown in the drawings. The lower end of said body 1 is also adapted for attachment to a drill-bit 4 Fig. 1, preferably by means of an'internal tapered screw-thread 5. As shown in the drawings, the body 1 of the underreamer is form a slightly eccentric with respect to said end screw-threads 3 and 5 and the axis of the drill-bit +l,'fo1 a purpose to be hereinafter set forth.

An axial bore 6 is formed within the body 1, extending upwardly from its lower end, and a radially disposed elongated slot 7 extends from said bore 6 to the exterior of the body. As shown particularly in Figs. 8 and 9 of the drawings, the rear or inner portion of said slot is the full width for its entire length, but the outer portion is narrowed at its upper end, as at 8, forming lateral inwardly facing shoulders 9.

A recess 10, Figs. 7, 8, 10 and 11, is formed in the rear wall of the axial bore 6 opposite the wide portion of said slot 7, said recess having a function to be presently described.

Within the slot 7 is carried a cutter meme ber 11 provided with a cutting-edge 12. The upper portion of said cutter 11 is formed with a narrow tongue 13, adapted to lie within the narrow slot portion 8, and is provided with shoulders 14 adapted to lie behind and engage the shoulders 9 in said slot, for the purpose of retaining said cutter within said slot. Said cutter 11 is further provided with a rear bearing face, comprising a. fiat upper projecting bearing lug 16, Figs. 2 and T, the latter being semi-circular in form, to seat firmly against the rear wall of the cen tral bore 6.

A substantially cylindrical mandrel 17,.

slidably mounted within the central bore 6, is provided with a flat forward face 18 against which the flat rear face 15 of the cutter 11 is adapted to bear. A slot 19 is formed within said mandrel 17, within which is received a lug 20 extending rearbody of my underreamer,

portion 15, and a wardly from and preferably formed integral with. the upper portion of said cutter, so that both mandrel and cutter move togather in a vertical direction.

The upper portion or stem 17 of the mandrel is surrounded by a compression spring 21, by means of which said mandrel and the cutter 11 are normally held in their uppermost positions. The lower end of said spring bears upon a key 22 lying within alined transverse slots 23 and 24 formed in the body 1 and the mandrel stem 17 respectively; Said key 22 is notched on its upper side, as shown at 22, the lower end of the spring 21 resting within said notch, and thereby retaining said key in position laterally. When it is desired to remove said key, to permit the withdrawal of the mandrel and the removal of the cutter 11, as will be described more fully hereinafter, the spring 21 may be temporarily lifted out of said notch 22 by means of any suitable tool, not illustrated, inserted through the slot, 23 in the body 1, said slot being of suiiicient size, as shown in Fig. 8, to permit the entrance of such a tool.

- The functional, or working position of the movable parts of the underreamer is shownin Fig. l'. In this position, the cutter 11 is extended, to bring its cutting edge 12 into contact with the side of the well-bore (not illustrated)." Ample provisions are made for transmitting the shocks, due to the normal operation of the device, from the cutter 11 to the body 1, the upper end of said outter having a semi-cylindrical seat, at 25, Figs. 7 and 8, in the upper end of the slot 8, and having a bearing for its rear surface 14 against the fiat forward surface 18 of the mandrel 17. lhe lower portion of the cutter is supported. by the semi-cylindrical bearing of its lug 16 against the wall of the central bore 6.

For retracting the cutter into the body of the reamer, to permit the withdrawal thereof through the well casing, ashoulder 26, Figs. 2 and 7, is formed in the outer face of said cutter, said shoulder engaging the toe of the foot 27 of the wellcasing 2, when the reamer is drawn up, as s own in Fig. 7. Continued upward move ient of the reamer body causes thecutter 11 and the mandrel 17 to move downward, relatively to said body, until the rear bearing in 16 of said. cutter entersthe notch 10. his permits the cutter to move into the body of the reanier', and to occupy the position shown in Fig. 2, in which heldby the contact 0 its outer face 28 with theinside of the well-casing. The body 1, being eccentric, bears against the well-casing at its back for its entire length, while said outer cutter face 28 provides a bearing on the opposite side, thus accurately and centrally guiding thedrill bit l. so that the osition said cutter is- 1 passes cutting edges 4' thereof pass freely through the casing. A drainage duct 29, Figs. 2, 7 and 8, is preferably provided for permitting the escape of mud and rock particles from the lower portion of the cutter slot 7.

On account of the comparatively large area ofthe bearing surfaces 25, 15 and 16, of the cutter l1, and the length of the mam drel 17, very little wear occurs at these points, and the body and mandrel therefore last for a relatively long time. The cutting edge 12 of the cutter, however, naturally wears rapidly, necessitating the renewal of said cutter. This may be accomplished. very easily, by withdrawing the key 222 in the manner previously described, and allowing the mandrel 17 and the cutter 11 to drop down until the shoulders 14: of said cutter are free of the shoulders 9 in the sides of the slot 7. lhe cutter may then be with drawn laterally through said slot. The

mandrel, if necessary, can also be easily re moved, by allowing it to drop out the lewer end of the central bore 6.

Having thus described my invention, what I claim as new and desireto protect by Let ters Patent is 2-- 1. An undeireamer comprising a body portion formed with an axial bore and a lineally disposed slot communicating with said bore and having a relatively deep portio a relatively shallow portion, a semicyliidrical upper end and a semi-cylindrical ba v a cutter member carried within said slot and adapted for lineal sliding movement and swinging transverse movement, said out-- ter knember having a cutting edge adapted to protrude beyond the body when said cutter member lies in the shallow portion of said slot, and to be retracted within said body when in the deep portion. of said slot, and sand cutter member being further formed with semi-cylindrical bearing faces adapted to seat against the upper end and bash oi said slot when said member is in theshallow ortion thereof, and said cutter member bemg also formed on its back with adat hear-- ing face; a lineally movable mandrel fitting closely within the bore of the beat portion,

said mandrel having a fiat face forming a said cutter member slot, and to be retracted Within said body when in the deep portion of said slot, and I being further formed with semi-cylindrical bearing faces adapted to seat against the upper end and back of said slot when said member is in the shallow portion thereof, and said cutter member be ing also formed on its-back with a flat bearing face and a lug projecting rearwardly therefrom; and a lineally movable mandrel' fitting closely within the bore of the body portion, said mandrel having a' fiat face forming a lateral thrust bearing for the-flat face on the cutter back and having also a slot in which the lug of the cutter member engages.

3. An underreamer comprising a body portion adapted to be passed through the casing of a well, and having means at its upper end for connection with a drilling line and means at its lower end for connection with a drill bit, said body portion being asset laterally with respect to said end connection means; and a cutter member carried Within said body portion and adapted to be protruded therefrom and retracted thereinto, said cutter member having an elongated bearing surface adapted to project beyond the side of said body portion when said outter member is retracted, said bearing surface being adapted to bear against the side of the Well-casing and to coact with said ofl'set body portion to guide said drill bit centrally within said casing. I

In testimony whereof I have signed my name to this specification in the presence of two subscribing Witnesses.

WILLIAM M. KECK.

Witnessesi i BOOTH, D. B. RICHARDS. 

